A fixing device for use in an electrophotographic image forming apparatus is known in the art, which includes an endless film, an infrared heater (heating element), and a reflecting plate for reflecting infrared radiation from the infrared heater toward a heating plate. In such a fixing device, if printing for small-sized recording media is carried out continuously, the temperature increases too much at both end portions of the heating plate where the recording media do not pass through. For this reason, an end-side rotatable reflecting plate is provided so that the radiant heat emitted from the infrared heater can be reflected by the rotatable reflecting plate toward a center portion of the heating plate.
However, if a fixing device is designed to reflect the radiant heat emitted from the infrared heater toward a printing area on small-sized recording media as with the aforementioned fixing device, it is necessary to dispose the end-side rotatable reflecting plate a large distance away from the infrared heater in order to keep a space required for movement of the end-side rotatable reflecting plate. This disadvantageously leads to an extremely large-sized device.
Further, according to the aforementioned fixing device, when a small-sized recording medium is printed, the end-side rotatable reflecting plate is tilted inward. However, in other cases, such as during printing of recording media other than those small-sized media, the radiant heat emitted from the infrared heater flows outwardly in a width direction (including diagonal directions) of a recording medium and leaks to the outside, so that the heat from the infrared heater is not effectively utilized.
It would thus be desirable to provide a fixing device which is compact and can effectively utilize the radiant heat emitted from the heating element.